Jump to content
Get that dancing monkey off your back! Read more... ×
Sign in to follow this  

2013 rmz250 loud noise after 13:8.1 (HCP) top end install

Recommended Posts

Everyone please help me! Im so worried that my motor may go at any time. I have a 2013 rmz250. after 45hrs on stock piston, i installed a Vertex 13:8.1 HC Piston kit. Thats all i did. No other upgrades. The elevation im at is 5800 ft. Im running vp VPR fuel (50/50) mixture. Also have installed permenently the grey coupler. Iv spoken to wade wilcox at injectioneering and another dude from california who is a rep for Vertex USA. They both said my bike would run great with it and the VPR 50% mix and grey coupler. They are right ...It runs great. BUT!!!! Now i have 17 hrs on motor and its making some SEMI loud clacking sounds. I thought it was valves. So last night i checked Valve Clearance. Intake & Exhaust clearance are spot on. The Timing is spot on. The cam chain has great tension. I checked the compression at WOT is 118 psi. The service limits are 57 - 114psi manuel specs. Bike starts 1st or 2nd kick everytime when cold or hot. Has great throttle response. But when im on the throttle, i hear loud clacking. Like it is the valves or rod. I dont know what else to do without serious;y diving deep.. HEEEEELP! BTW! I have a 2012 rmz4540 and even that monster is quiter than my 250.

Share this post


Link to post
Share on other sites

Sounds like detonation to me. I would siphon the gas out of there and put some new in with ethanol fee gas as your mixer. I would also try running 100% race gas. If that doesn't work, change it back to oem piston. Those hi comp pistons usually don't last very long.

Share this post


Link to post
Share on other sites

I was thinking the same thing.. I checked the plug, it looks good. A light Brown.. ill try running straight VPR.. anyone else have any input?

Edited by slowgs2001

Share this post


Link to post
Share on other sites

Does sounds like detonation. The other possibility is a bad rod bearing. Typically they lock up or lose power at high rpm,but they can just get loud. Easiest thing to do is run straight high octane gas and see if it goes away. If it doesnt-you will need to tear it down and check tolerances on all the parts and inspect for damage. I have a hc piston but I run 100ll and have a power commander. I some time mix in vp u4. I would skip on the oxygenated fuel and just try a straight high ocatne fuel. This will rule out a lean condition also.

Share this post


Link to post
Share on other sites

What type of vp do you recommend? Straight VPR? Maybe straight c12? Or maybe u4.4 straight?

C12 is straight gas not oxygenate. U4 is highly oxygenated. Power commander i got on sale for $250. Check internet-guarantee its on sale this weekend!

Share this post


Link to post
Share on other sites

C12 is straight gas not oxygenate. U4 is highly oxygenated. Power commander i got on sale for $250. Check internet-guarantee its on sale this weekend!

. So should I run straight c12 or u4? I don't understand fuels.. that's one thing I never took time to understand

Share this post


Link to post
Share on other sites

C12. Then check the plug. What is your elevation? Just try running the race fuel you have now straight. Dont cut it with pump gas. Make sure you have just straight high octane gas in you tank and see how it runs. If it still has the knock-going to have to see whats up. If it goes away-then you know to just run straight high octane.

Share this post


Link to post
Share on other sites

Ok ill buy some c12 next week.. I have no race fuel right now.. also I'm on the net looking for power commander but there are a bunch of different ones.. which ones are best?

Share this post


Link to post
Share on other sites

C12. Then check the plug. What is your elevation? Just try running the race fuel you have now straight. Dont cut it with pump gas. Make sure you have just straight high octane gas in you tank and see how it runs. If it still has the knock-going to have to see whats up. If it goes away-then you know to just run straight high octane.

here is my comp test and spark plug color

1378062871122.jpg

1378062886965.jpg

Share this post


Link to post
Share on other sites

Does sounds like detonation. The other possibility is a bad rod bearing. Typically they lock up or lose power at high rpm,but they can just get loud. Easiest thing to do is run straight high octane gas and see if it goes away. If it doesnt-you will need to tear it down and check tolerances on all the parts and inspect for damage. I have a hc piston but I run 100ll and have a power commander. I some time mix in vp u4. I would skip on the oxygenated fuel and just try a straight high ocatne fuel. This will rule out a lean condition also.

ac717 , is this what you have ?

Share this post


Link to post
Share on other sites

Yup. Power commander v. Works really good and easy to program. I had tried another efi programmer and didn't care for it. The power commander and the vortex units are good. The yosh MX programmer is good but its like a $1,000. I Dont feel changing ignition timing is worthwhile,so the pcv will do the mapping and set throttle sensor. When programming,just try the mod/pipe map they offer and tweak from there. Bike will pull stronger and smoother. Wiht the high compression piston and the programmer..throw some VP u4 in and it feels just as strong as my rm250. I just got done riding my rm250. Got a flat so I jumped on my rmz250. On the bottom end the rmz250 can pull a taller gear than the rm250. Its crazy the power these little bikes can make. I remember when it was out of the question to break 40hp out of a 250f. Now its pretty easy and bikes like the KTM are making 40 stock. Thing I like about the Rmz is the power is very broad.

Share this post


Link to post
Share on other sites

Since you have experience with this PCv. Is it really worth the money? And do I have to physically tune it myself or do I just download maps and run it? I am seriously not wanting to have to pull hair out trying to tune.

Share this post


Link to post
Share on other sites

Since you have experience with this PCv. Is it really worth the money? And do I have to physically tune it myself or do I just download maps and run it? I am seriously not wanting to have to pull hair out trying to tune.

They provide 2 or 3 maps with the unit. Its very easy to adjust the maps. Its not scary or frustrating. Worse that it can do is run flat. Think of mapping as just air/fuel ratio. If you ever made a potato gun...same physics. When you get the right amount of fuel-it makes power if its too lean or rich-the engine ignites fuel wrong. Its really simple,but just like jetting..always a sweet setting. You will be amazed at the power a properly mapped bike will be.

Share this post


Link to post
Share on other sites

Ac717.. you have been a great help to me.. last q..will I have to refine the power commander each and every time I do an upgrade? And will I have to retune every time I travel with the bike?

Share this post


Link to post
Share on other sites

Nope. Once you make a map,it loads up and the bike is ready to rip. You can hook a laptop up anytime and male changes. The power commander goes behind front number plate or in the air box (depending on year). The bike powers it and the program inside the PC just speaks to electronics. Its actually simple electronics. Its just giving parameters outside of the stock mapping.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×